EXTHACTS. 113 



beetles kept as a control. Large nunil)ors of eggs were 

 deposited after exposure, ])ui were infertile, though eggs 

 from the control beetles hatched normally. Larva) were 

 given an exposure of 600 niilliani{)ere minutes, other con- 

 ditions of the experiment being the same as with the adults. 

 While no immediate effect was apparent, the treatment had 

 the effect of stopping activity and develo})ment, the larvre 

 remnined in a dormant condition for a prolonged period. All 

 treated larva) died before reaching the pupal stage. {Runner^ 

 G. A., Jl. Agric. JResearch, Waslnnyton, J).C., vi., jVo. 11, 

 12th June 1916, pp. 383-388.) 



An X-ray apparatus is used at a cigar factory at Tampa 

 against Lasioderma serricorne (cigarette beetle). The 

 machine can treat 40,000 cigars an hour. After being placed 

 in boxes, they are put on a belt which travels through the 

 machine a distance of 23 feet in 20 minutes. The apparatus 

 contains two X-ray tubes,, operating at 45,000 volts, and a 

 current of 100 milliamperes is passed through them. B^or 

 4J minutes the cigars are exposed to the direct rays and to 

 reflected rays for the greater part of 15 minutes. The 

 machine is extremely simple in construction. It enables 

 cigar-manufacturers to carry on work throughout the year, 

 whereas, up to the present, it has been done chiefly before 

 Christmas on account of the loss in large stocks due to 

 infestation by L. serricorne. (Skerett, R. C, Scientific 

 American, iV.r., cxv., No. 15, 1th Oct. 1916, pp. 319 and 

 336.) 



Locusts : Gi^eat Invasions, — Past history tells us to expect 

 sudden invasion by vast swarms of flying locusts coming 

 from parts unknown. There seems no suspicion that these 

 unheralded nn'grations came from northern Africa, and the 

 physical conditions of the continent seem to preclude such a 

 contingency. On the other hand, all evidence goes to show 

 that these locust phenomena originate in or near to the arid 

 western core of South Africa. There is a general consensus 

 of opinion amongst older inhabitants of the Cape Province 

 that these invasions came from the north or north-west, of 



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